Automatic telephone system



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l lNvl-:NToR v WWU- RED T. POWELL.

ATTORNEY Jan. 3o, 1923. 1,443,646

AuToMArvl: lSYSTEMI F1 LED MAR. 8. 1920. 2 SHEETS-SHEET 24 l Jr UNE

ISWIYCMFUR AT roRNEY VET" Patented den 3%, l923 STATES Wnrnnn T. retirant; or nocnnsrnn, NEW Yoan, assrenon 'ro Tir-rn srnonnnne- Emsa CARLSON TELEENE PZANUFACEUBENG COIIANZ,y GF ROCHESTER, NEW' YORK,

A CORPOEAION'OF NEWT YORK.

' AUTOMATIC TELEPHONE- SYSTEM.

appiieanon ena Maron s, 192e. serial no. 363,971.

To a-ZZ when?, et' may concern.:

neu and usc ul lmp nements in autotic t elephone Systems ot which the iolng a tull, clearj concisey and exact description.

rhis invention relates to telephone systems, and more particularly to telephone t empl auii'nnaic switches in i-onioletine' a telephone coz'mection between calling and called telephcne lines.

y it the purpose ol the present invention to prrry fle a telephone sistem in which the conversational circuit entends only through non-numerical sivitcho The various features included will appear from the detailed description and claims.

,The drawings With Fig. 1 F 2 diagrammatically representa portion of a telephone system embodying the present intention. it the upper lett hand corner ot Fig. l there is shown the operating circuits ot a line or trunit selecting suitch ind' 7iduzfl toa telephone line which herein referrer.. to as a calling subscrib- -'s line. rt the rigl of the dotted line there is shown one t nl: or linl; circuit 1th the associated operating circuits oit a i sender, corner of Fig. 2 there is shown the operatng circuit of a linl; or trunk selecting switch individuel to a telephone line, which is herein referred to as a called sabscribers li e. At the center and at the right of Fig.

2 there is shown a group of ten relays common to the exchange, each provided with ten sets of contacts. Fig. Slindicates that both ends ot each trunk or linlt circuit ter- .ninates in each line or trunk selectiiig suitch.A This shown for the tiret tour trunk or link circuits. but it u'ill be understood that the remaining twelve contacts placed above At the upper leit'handA of .which isprovided with an individual line switch havingV twenty-one contacts. Since, this switch is ot' the advance to normal type, one of these ,sets of e contacts serves home position, While ten sets ot' contactsserve 'as terminals for the out-` going end of the-ten trunk or link circuits provided; While ther otherten sets oi contacts serve as the incoming ends of these ten trunk or link circuits". lt Will be understood that' the line switch is notlimited to the advance'tonormal type, but may be of the return to normal type, or may he arranged so that the line switch remainsI in engagement `with the trunk circuit lastl used. Similarly the number of trunk .or

link circuits is not limited toten, but this' nun'iber has been selected because in practice this many trunks will care for the number ot' simultaneous connections. Y

It is believed that the invention will best be understood by describing the method ot establishing' a telephonevconnection from a calling substation at A; toa. called substation indicated at B. When the calling subscriber at A removes his receiver from its sivitclihook (not shown), the linev relay LR individual to this line is operated over a circuit extending from grounded battery, left hand *Winding of this'relay, inner upper armature and back contact ofthe cut-olf relay CQ, through the calling substation and upper-most armature and back contact of relay C to ground. The line relay LR is energized in this circuit to attract its armatures7 and at-its inner `armature and front contact completes an operating circuit for line'switch into engagement Wit-h the set of g terminals individualfto the lirstl outgoing trunk terminating at the sivitch. Itthis trunk circuit is idle, the motor magnet Will be shunted, and the line .relay LR will be held operated andcut off relay CO energized by a circuit extending from grounded battery resistance, back cont-act and armature of the motor magnet, right hand winding, front contact and armature ot the line relay LR, upper winding ot the cut-oil3 relay CO, armature and back contact olz slow releasing relay G, trunk test brush 19, test conductor 8, bach contact and armature ot' slow releasing relay 9, conductor 10, units register brush 11 in its normal position, conductor 12, tens register brush 13, also in its normal position, back contact and armature ot slow releasing relay 14, back contact and armature of impulse relay IMI3 to ground. As soon as the trunk is seized for use, its test circuit just described is opened by the energization of the impulse relay IMP and later by the operation ot' the slow releasing relay 141, and subsequently when the tens and units register brushes 13 and 11 are moved from their normal position.

In this description it will be assumed that the first trunk circuit test-ed was busy, but that the second trunk circuit which is the one shown in the drawings, idle. Under this assumption as soon the calling line switch has been moved from its normal position, a second operating circuit for the motor magnet- MM et the line switch is closed troni ground,winding of this magnet, oit normal Contact 15 now closed, innermost lower armature and baci; contact of the cut-ott relay CO, armature and back Contact of the motor magnet lli/IM, and resistance to grounded battery. nder the control of this circuit the motor magnet advances its brushes 1G, 17,18, 19 and 20 into engagementwith the terminals ot the trunl; circuit he. n shown, whereupon the line relay LR is heid operated and the cut-off relay CO will be energized in a circuit similar to that previously described.

rIhe cut-oil relay when operated closes a locking circuit for itsel't' from grounded battery, winding of relay 21, conductor 22. holding brush 1S, lower winding ot the cutoitl' relay' GO, its front contact and armature, normally open contact 15, and winding ol the motor magnet MM to ground. The right hand windingol the slow releasing relay 6 has an operating circuit iu multiple with the circuit last described. causing this relay to attract its armatures. .-ts soon as the cut-oit relay attracted its armatures. il' opened the original energizing circuit et the line relay LR and closed the line circuit to brushes 1G aint 1T oi the line switch. where upon a circuit is closed including both windings ot the impulse relay IMP inseriesl to grounded battery. This last named rela).v attracts its armature, and at its front contact closes a circuit for opera-ting the slow releasing relay 14. This relay tt attracts its armatures to complete an actuating circuit for slow releasing relay 9 and to close break points in circuits te be described.

.as scones relay '21 attracted its armatures. relay 35 was actuated in a circuit closed from grounded battery, winding of this relay, tront contact and armature of relay 2l, back contact and armature olf relay 231 to ground. l'ilhen operated, relay 3:3 closes a locking circuit for itseltl through the front contact and armature olf relay 21, back contact and armature ot relay 36, upper liront contact and armature of relay 35.

rllhe apparatus is now in condition to re` yceive the impulses corresponding to the designation ot the wanted subscribei"s line. Let it be assumed that the number of this line is 39. T he calling subscriber thereupon operates his dial to transmit three impulses corresponding to the tens digit ot the wanted number. In response to each ot these impulses the relay IMP retracts its armature. At the first retraction of its armature a circuit is closed trom ground, armature and back contact ot this relay, inner armature and front contact ol relay 14, Winding of the slow releasing relay 23 to grounded battery and the relay actuates its armatures. A circuit in multL ple with that last described is simultaneously closed from grounded battery, winding of the motor magnet 24, armature and back contact of the switching relay 25, lett hand front Contact and armature et relay 14, and back Contact and armature ot relay IMP to ground. In response to each of these tens impulses the motor magnet 2J: of the tens register operates its brushes 13 and 2G (Fig. 2) until the brush 13 is in engagement with contact 27, and the tens register brush 26 is in engagement with contact 28. At the close oi" this series ot impulses, the relay IMI) attracts its armature -i'or rela tively long interval, and at its back contact and armature opens the energizing circuit for the slow releasing relay 9.?) for a. long enough period so that this relay retractsits armatures. At the outer armature and back contact of relay il?) a circuit is closed troni ground, continuity spring winding oi. switching relay brush 12%, contact 2i. back contact, armature and winding of thc motor magnet 24 to grounded battery. The lnotor magnet "ift does not operate in series with the relay L5. but the relay 25 is actu ated and ein, :s a locking circuit tor itselt 'troni Tuind. through .its armature and continuity spring to grounded battery at thc magnet :lf-l.

The calling subscriber thereupon transmits il impulses corresponding tothe units digit Aot the wanted number whereupon the impulse relay Ili'iP again vibrates its armatures to eiect the energizat-ion olt the relay 23, but now these impulses are repeated to the motor magnet 30 ot the units register. Theoperating circuit ot this last named motor magnet Vextends* from grounde'dbat tery, its winding, back contact and armature ot' relay 31, lett hand t'ront contactV At the close ofthe units series ot impulses, the relay lMlD again attracts its armatures to interrupt the operating circuit of the slow releasing relay 23, and this relay de-energizcs to close a circuit from ground, its armature and back contact, Winding ot relay 31, units register brush 11, contact 33 with Which it is now in engagement, armature, back contact and Winding of 'the motor magnet 30 to grounded battery. The motor magnet 30 does not energize in series with the relay 31, but the relay 31 is operated and closes a locking circuit for itself from ground, through its inner right hand armature and front contact to grounded battery at motor magnet 30. With relays 31 and 35 operated and with the extended starter Wire in the condition shown in Fig. 1, relay 36 will be operated to initiate the operation of :the called line switch. Relay 36 is actuated in a circuit traceable from grounded battery, winding ot' this relay, lower-most front contact and armature of relay 35, outermost armature and continuity'spring of relay 31 to the bacl: contacts and armatures ot relay 3T to ground. Relay 36 attracts its armatures and at its lett hand armature and back contact opens the locking circuit ot' relay 35, While at its inner right hand front Contact and armature a `circuit is closed from ground over conductor 37, brush 26, contact 28 ot the tens register, Winding of relay 39 to grounded battery. rlhe relay 39 attracts its armatures and closes its ten sets of contacts.

t will be iirst assumed that the Wanted' line is idle under which assumption a circuit will be closed from ground, outer-most right hand armature and front contact of relay 36, conductor 40, right hand Winding of relay 38, brush 32 and contact 34 of the units register, conductor 41, lower-most armature and back contact or' the cut-oft' relay CO of the called line, and left hand Winding oi' relay 42 toture and iront contact o'l relay 42, lowermost armature and baclrcontacts of relay C0', outer-most left hand armature and contact of relay 42, outer front Contact. and f armature of relay LR to ground. The relayy 42 is held energized in a circuit in multiple of that last described including its lett hand Winding.v .Also when the line relay LR of the called line attracts its armature,"

an `operating circuit is closed for the motor magnet 44 of the called line switch from ground, Winding of this magnet,l normally closed contact 45, inner right hand armature and front contact and Winding of line relay LR', armature and back contact ot' motor magnet 44, and resistance to grounded battery. Under'the control of this circuity the motor'magnet 44 moves its brushes 46, 47, 48, 49 and 50 into engagement with the terminals corresponding to the first trunk terminating at the called line switch. li' this trunk circuitv is they one that has been seized by the calling line switch, the motor magnet 44 will cease to be actuated otherwise it Will be operated in a circuit traceable from ground, Winding of this magnet, normally lopen'contact 46, inner-most lower contact and armature of relay CO", armature and back contact of motor magnet 44 and resistance to grounded battery. Since the relay 42-is operated at this time, test brush 50 instead of the test brush 49 is now effective to hunt for the trunk or link circuit seized by the calling line switch. As soon as the contacts of this trunk circuit are reached, a circuit Will be closed from ground, outer-most lett hand front contact and armature of relay 38, conductor 51, test brush 50, right hand front contact and armature of relay 42, upper winding of cut-od relay CO, inner right hand armature, 'front Contact and Winding of `line relay LR', armature and back contact of motor'magnet 44,*and resistance' to grounded battery. The' cut-od' relay CO attracts its armatures and aty its inner-most lower armature'and back contact opens up'thev operating circuit of the motor magnet 44, WhileV at the upper armatures and backcontacts of this 'relay the energizing circuit ofthe line relay LR which is 'effective on the initiation ot a call, f is opened and at the upper armatures and front contacts of this relay the called line is extended to the'line switch brushes 46and 47 now in engagement with the seized trunk circuit. At the inner lower armature and front contact ot the cut-ott' relay CO a loclring circuit is closed from ground, winding of the motor vmagnet 44, contact 46, armature,-front' contact and lower Winding of l cut-oil" relay CO, holding brush 48, conduc`.

tor 52, armature-.and front contact of relay l 9, noW energized, Winding of relay 53 to grounded battery. A circuit in multiple with that just described includes the right hand winding ot relay ft2 so that relay Ll2 is also held energized. As soon as the relay 523 attracts its armatures the locking circuit ot relay 3 is opened and this relay deenergizes, while at the lett hand armature and front contact ot relay 53 a circuit is closed from ground, armature and baclz Contact ot battery feed relay 54, armature and 'front contact ot' relay 53, Winding` of the ringing relay llll .l and resistance to grounded battery. The ringing relay attracts its armatures to close a ringing;` circuit to the called line extending from the ringing machine generally designated 55, right hand Winding ot the trip relay TRIP. lett hand tront contact and armature ot' ringing relay RNG, conductor 56, line switch brush l?, innen most upper ,trontcontact and arn'iature of cut-oil relay CG. through the substation circuit and bell ot' the calle-:l subscriber. uppermost armatur r and front contact ot cut-orf relay (TV, line switch brush 4G, conductor 5T. resis Ance 55). right hand armature and Yfront co1. act otl relay lllG, inner right hand armature and front contact'ot relay 53, and outer lett hand armature and front contact ot' relay lilto ground. rlfhe low resistance 59 causes a ringing tone to be heard in the receiver at the calling substation, so that the calling` subscriber knows that ringing' cu rent has been applied. When the Wanted subscriber answers by removing his receiver from its siyitchhoolr, the trip relay attracts its armatures and short circuits relay RNG. This rela;T then releases and closes a locking circuittor relay TRIP, and completes an energizing` circuit 'for relay This loclrine' circuit for the trip relay is closed from grounded battery, its le'lt hand Winding, armature and 'front contact, right hand back contact and armature of the ringing relay. right hand front contact and armature of relay 53, conductor 60, outer front contact and armature of the slow releasing relay 14 to ground. As soon as thev battery feed relay attracted its armature, it closed a substitute holding' circuit tor the slow releasing relay 9 which controls the release of the called line snf'itch.

lt will now be assumed that when the relay was energized atter the setting ot the tens and units register, the wanted line was busy. llnder this condition when ground is extended over conductor -ll to the called line switch. this circuit Will be opened at the lower-most armature and bach conta-cts of the cut-ott' relay CU. Therefore the line relay LR and the slow releasingrelay 42 Will not be actuated and the called line switch Will not be operated. Therefore relay 53 will not attract its armatures, so that a circuit will be completed to the calling line to transmit a vbusy ltone from the busy machine BZ, lett hand armature and front contact ot relay 2l. inner lower bach contact and armature ot' relay conductor (il, middle back cont-act and armature ot' relay 88, outer baclr Contact and armature of relay 523, conductors 58 and 62 to the calling line, conductor 63, righthand Windingot relay lll/ll) to ground. lWhen the calling' subscriber receives this busy signal he replaces his receiver on its switchhook to cause the release of his line switch.

ln the present arrangement, the calling subscriber controls the release ot' his line switch While the called subscribers line switch .is under his control. TWhen the calling' subscriber replaces his receiverv on its switch hook relay IMP de-energizes and a circuit is closed from ground, armature and back contact ot' relay lMP, inner armature and front contact ot relay la still energized, winding ot slowY releasing; relay 23 to grounded battery. NVlelay attracts its armatures and shortly afterward relay le de-energ'izes, but a circuit is momentarily closed trom gro-uml, right hand armature and bacl; contact ot relay lll, inner armature and front contact of relay 23, conductor to short circuit the cut-olll relay C@ and the relay 6, causing' them to retract their armatures, but relay 2l is held operated. liter a Very short interval the relay 23 retracts its armatures restoring relay 2l. lllhen relay C@ retracts its arma-tures an operating' circuit is closed tor the motor magnet MM of the calling` line switch ex'- tending' from ground, Winding' ot this magA net. contact l5, inner lower armature and back contact of cut-oft relay CO, armature and back contact of the motor magnet MM and resistance to grounded battery. Under the control ol" this circuit the motor magnet advances its brushes by interrupting its own circuit until the home position ot the line switch is-reached. at which time contact l5 will be opened and contact 5 closed.

lllhen the alled subscriber replaces his receiver on its switchhoolr, the battery feed re lay 5e* dc-energires and opens the operating circuit of the sleufv releasing' relay f). Alfter a short interval, relay 9 deencrgizes and opens the holding circuit ilior relays 53, U0 and il@y causing' these relays to retract their arimitiii'es. it the inner lower armature and back contact ot cut-olll relay (YV an operating' circuit is. closed tor tlieniotm magH net lll of the called liuc switch. which circuit extends iroin ground, windingA ot the motor magnet, normally open Contact flo, armature and backcontact of relay (.llll, armature and back contact ot the motor magnet al, and resistance to grounded battery. The motor magnet by inteuruptinze` its own circuit advances the brushes of the line switch to their normal position at which the contact e6 is opened and contact l5 'inflar-zee closed. thus leaving the called line switch and its circuit-s in condition for use on a succeedingl call.

Let it be assumed that B desires to call e,

and that the designation of As line is :HT-0G. Under tl s assumption when B removes ius receiver rom its sivitchhoolr, his line switch will nou advance to the outgoing end ot an idle trunl; instead ot to the incoming end ot such a trunir circuit as in the case when his line 7mis that called. After the seizure oi an Edle trunk circuit, E Will then operate his dial First, to send tivo impulses to set the tens register and thereafter six impulses to set theA units register. l tertl'iese operations when the relay correspoiniing to 3G ot Fig. 'l is acti'iated to eitect the completion oi a call, relay 'TO instead ot Will be open ated Iand ground will be extended over con` ductor l0 through the right hand Winding ot a relay similar to 38, to a units brush similar to 32 nou7 in engagement with its contact 71, contact 72 ot the relay TO, conductor 73, loivermost armature and back contact oit relay` CO, left hand winding ot relay 6 to grounded battery. Relay 6 at-- tracts its armatures and thereby closes an operating circuit for the line relay LR trom grounded battery, left hand winding ot this relay, inner left hand armature and front, Contact of relay 6 to ground at the outer right hand armature and Jfront contact ot relay 3G, over conductor 73. The relays LR and 6 are locked operated and the motor magnet MM of the line switch individual to As line will operate to seize the incoming end of the trunk circuit which has been seized by the line switch individual to Bs line. Thereafter the ringing and releasing operations will take place lin the manner previously described.

In accordance with another feature orn this invention if it is desired to provide several substations having the same designation for the ot any subscriber, means are provided to automatically connect a calling subscriber with some one ot these substations as long as any one or' them is idle. To accom-- plish this result conductors shown at ot rFig. l and T6 shown at Fig. 2 are employed.

Let-it be assumed that the subscriber' A is provided with two or more substation sets, and let it further be assumed that uheniaA was called his iirst substation Was busy in which case the cut-ott relay CO will have its armatures attracted, so that When conductor 'T3 is extended to the first substation circuit individual to A, it will be further extended over conductor 75 to a second line switch circuit and telephone substation identical With that shown in the upper lett, hand corner ofFig-1 l. The operation o this second line switch will be. similar 'to the operation of the other line switches in seizing the incomingend ot a trunl; circuit that is new incomplete.

one line Will be provided for the use ot each subscriber in which case conductors i5 and Will'be omitted.

ln the early part ot this description reference was made to an extended starter wire circuit. This circuit functions to effectA the connection of telephonelines, one at a time, atfter he restoring ot ther Wanted i'nu'nbers on the register senders.

by reference to lfig. l it will be noted that the starter ivire extends from ground at the armatures and back contacts ot relay 3?, which is common to all the register' senders, over conductor 80, continuity springy and contact 8l of relay 31, vconductor 82 and through the continuity springs and contacts similar to 8l of relays similar to 3 1, through the series of register senders. lt will thus be seen'that Whenever a relay 3l of any ot the senders is operated, it interrupts the starter Wire to succeedingiscnders in the series at this contact 8l. A further ydescription ot thestarter Wire is not believed to be necessary since the use ot such Van arrangement tor other purposes has been-previously used in this art. f y

n the present system the circuits have beeny so arranged that when either party abandons the connection a busy tone Will be transmitted to the party maintaining the connection to indicate that the connection is rEhe circuit for transmitting this tone to the calling party is identical with that employed in transmitting the busy tone to this party when the called subscriber is busy. rThe circuit for transmitting this tone to the called party extends fromthe busy machine, armature and back contact of relay 2l, conductor Si, outerright hand Vliront contact and armature ot relay 53, conductors 58 and 5T to the called substatioin' conductor 56, armature and baclr contact ot' ringing relay BENQ, and right hand Windingl of relay 54 to grounded battery.

llVhat l claim is 1.111 a telephone system, plurality of telephone lines, a trunk selecting switch Jfor each of said lines, a trunk circuit common tov said lines, a sender individual to said trunk, said sender including rotary register switches arranged to be variably adjusted from a distant point, means tor causing each trunk lselecting switch to seizeone end of said trunk when its associated line originatesa call, and means including' said sender tor y'causing each 'ot said trunlr selecting switches to seize the other end oty said trunk circuit when its associated line is called.

ln a telephone system, a plurality ot telephone lines, a trunk selecting switch individual to each ot said lines, a plurality ot trunk circuits common to said telephone lines, each of said trunk circuits being,` provided with a sender, both ends of each trunk circuit terminating in each trunlr selecting switch, and means including a sender for actuating trunk selectinO' switch to seize al trunk circuit in completing a telephone call, said sender includingregister switches arranged to be variably adjusted troni a distant point.

3. ln a telephone system, a plurality ot telephone lines, a trunl; selecting switch individual to each of said lines a plurality oi truuk circuits, each trunk selecting switch having' fixed contacts in which said trunl; circuits terminate and movable contacts in which a telephone line terminates, a sender individual to each trunk circuit, each trunk circuit having its ends conductively separated but inductively connected together, the ends ot each of said trunk circuits terminat ing in each of sait trunk selecting switches, and means including' a sender iloi' operatinga trunk selecting` switch in completing a call.

fl. In a telephone system, a telephone line, a trunk selecting switch individual to said line, a trunk circuit terminating at two points in said switch, av sender individual to said trunk circuit, said sender including a plurality of register switches arranged to be variably adjusted from a d istant point and arranged to be restored to a definite normal position when not in use, means for advancing' said trunk selecting` switch to one point when said line originates a call, and means including' said sender 'for advancing' said trunk selecting switch to the other point when said telephone line receives a call.

5. In a telephone system, a plurality ot telephone lines, a trunk selecting switch Yfor each of said lines, each trunk selecting switch having fixed contacts and co-operating movable contacts in which a telephone line terminates, a plurality ot trunk circuits terminating' in the lined contacts of said trunk selecting switches, a sender individual to each trunlr circuit for storing up the designat-ion of wanted lines, said sender including a plurality of register switches, means for variably setting said sender in response to impulses transmitted over' a telephone line, and means operative in response to the setting of said sender for causing the trunk selecting switch of the wanted line to cornplete the connection.

6. In a telephone system, a plurality of telephone lines, a trunk selecting switch individual to each of said lines, a plurality of trunk circuits terminating in each ot said trunk selecting switches, a register sender individual to each trunk circuit, means for variably setting said sender in response to incense impulses transmitted over a telephone line, a `group ot relays having;` a set oli contacts tor each of said telephone lines, and means controlled by said register sender and said group otv relays for causing' the trunk select` ing switch of the wanted telephone Yline to complete the connection.

7. ln a. telephone system, a plurality of telephone lines, a trunk selecting` switch for each of 'said lines, i plurality .of trunk circuits each provided with a sender, each reg'- ister sender including a plurality of progressively movable switches arranged to be rariably adi usted in succession "om a. distant point, both ends ot each ot -iaid trunk circuitsl terminating ineach ot said trunk selecting switches, and means controlled by a sender Ytor causing' two trunl; selecting switches to seize a trunk in completiup,` a connection between two telephone lines. Y'

8. In a telephone system, a ipilurality ot' lines, a progressively movable rotary line switch for each ot said lines, a plurality of trunk circuits each provided with a register sender, each register sender includinp` a plurality of step by step switches ot the advance to normal type, both ends ot each of said circuits terminating in each or". said switches, and means controlled by a register sender to operate two rotary line switches to seize a trunk circuit in completing' a connection between two telephone lines.

9. In a telephone system, a calling telephone line, a called telephone line, an individual trunk selecting` switch for each of said lines, trunk circuits for said switches, a regi ister sender individual to each trunk circuit, and means including a register sender by which the calling subscriber initiates the operation of' the individual switch o'j the called line to establish a. talking` connection between the two lines, said register sender having a step by step 'switch for each digit ot the designation oit. called lines.

l0. A telephone system comprising means for automatically trunking,` calling; subscribers lines into connection with the lines of the called subscribers, said means including' an individual trunk selectingv switch for each of said subscribers lines. trunk circuits for said switches, and a register sender individual to each trunk circuit controlled by the calling subscriber by which the individual trunlr selecting' switch of any called subscriber is operated to complete the trunking connection thereto, each register sender naving a plurality of step by step rotarv switches and operating' circuits therefor.

11. il telephone system comprising sub scribers lines, an individual trunlring switch for each or" said lines, trunk circuits to be seized by said trunlring` switches, a register sender individua-l to each trunlr circuit.y a calling' subscriber controlled automatic means including: a sender for causing' the l l (l Ici operation ot the individual trunk selecting switch oit the called line to complete a connection thereto, each sender having a plurality ot stephy step register switches and means toi' restoring said switches to normal on the abandonment of a call.

l2. il telephone system comprising subscribers lines, a plurality of trunk circuits, an individual switch 'toi' each line and functioning to seize idle trunl; circuits, a sender individual to each trunk, each sender including a plurality of rotary step by step switches of the advance to normal type, and means controlled by the calling subscriber by way of a sender tor lautomatically operating the called switch -tor Completing the connection to the called line.

13. i telephone system comprising subscribers lines, a plurality ot' trunk circuits, switches each having lixed contacts and movable contacts connected to a telephone line cooperating with said fixed contacts, trunk circuits terminating in said lined contacts, operating means for each line switch for connecting` a telephone line to a trunlr circuit, a sender individual to each trunk, each sender including a plurality ot step by step register siv'L-clies tor storing the several portions ot, the designation ot the called lines,means controlled over a calling line tor variably adjusting a plurality of switches ot a register' sender, starting circuits for said telephone lines, a plurality of relays for said telephone lines, each relay being common to a different group oit' lines, means includi one of the register switches of a selected sender tor actuating the relay coininon to the group 01"' lines containing the calling line to close a break-point in the starting circuit for said called line and means in cluding a second registerv switch tor closinga second break-point in said starting circuit whereby the switch of the called line isset in operation to connect said called line to the selected trunlr circuit.

l-l. ln a telephone system, a plurality ot teophoiie lines, a plurality of trunl: circuits, individual switches ttor extending said lines to idle trunks, each switch including fixed contacts serving as terminals for the trunk circuits, movable contacts for a telephone line and cfa-operating with said lined contacts, separate operating means for each line switch, a register sender individual to each trunk circuitA- each register sender including a plurality ot' switches arranged to be variably adjusted in succession over the calling line to store the indication of a called telephone line, a plurality ot starting circuits ifor setting in operation an individual switch which *functions to connect called lines to "elected trunks, a group of relays common o said lines and provided with a set ot :ontacts 'tor each telephone line and means ro wiincluding one ot'said register switches itor actuating the contacts ot one ot said relays, the starting circuit ot' the called line being completed through contacts ot the actuated relay and through the other switch oit the telephone line,imeans responsive to the initiationot a call on one ot said lines tor operating a trunk selecting switch toseize an idle trunk circuit and its associated registersender, means controlled over said calling line for variably operating the selected register' sender in accordance with the indication of a wanted vtelephone line, a plurality oi starting circuits one tor each telephone line, a group of relays common to said telephone lines having contacts controlling break-points in said starting circuits, means including one of the switches t the selected register sender for actuating some one or' said relays to close abreakpoint in a starting circuit and means including the other register switch ot the selected register sender to complete said starting cir cuit for causing a trunk selecting switch to extend the called line to the selected trunk circuit.

16. ln a telephone system, a plurality-ot telephone lines, a plurality of trunlr circuits, trunk selecting switches for connecting calling telephone lines to selected idle trunk circuits, each trunk circuit being provided with a register sender having a plurality oi switches for storing the designation of wanted telephone lines, means responsive to the'initiation of a call on one of said lines tor operating a trunk selecting switch to seize an idle trunk circuit and its associated register sender, means controlled over said calling line tor variably operating the selected register sender in accordance with the indica-tion ot a wanted telephone line, a plurality of starting circuits one for each telephone line, a group of relays common to said telephone lines and Vhaving contactsy controlling break-points in said starting circuits, means including one of the switches ot the selected register sender for actuating some one ot said relays toclose a breakpoint in a starting circuit and means includ-y ing the other register switch of the selected register sender to complete said starting circuit 'for causing a trunk selecting switch to extend the called line to the selected trunk' circuit, means tor disabling the starting circuit or busy called line and means responsive to the failure ot the completion oi the starting Circuit- 'lor applying a busy signal t0 the calling telephone line.

17. n :l telephone system7 telephone lines, several of said telephone lines being assigned to the use of one subscriber, a plurality 0r' trunk circuits, trunk Selecting switches 'For extending telephone lines to seleeted idle trunk circuits on the initiation of a cull, a register sender associated with each trunk Circuit, said register sender ineluding' a plurality 01c register switches for storing' the designation of culled tele-phone lineas, ineens for renderingt-elepliene' lines busy, means responsiif'e te said register sender for causing trunk Selecting switch m extend the called line to the selected trunk circuit :ind means for extending :L second telephone line assigned to the called subscriber to the selected trunk When the First line of the subscriber is busy und means for signalling' the Called telephone line.

1S. ln zi telephone system, telephone lines7 several of said telephone lines being z1ssigned to the use of one subscriber, e plurality of trunk circuits7 trunk selecting switches for extending telephone lines to selected idle trunk circuits 0n the initiation of a ealL a, register sender including a plurality of register switches for storing tlie designation of called telephones lines, means for rendering telephone lines busy, means responsive to said register sender for causing a trunk selecting` Switch to extend the called line to tlie selected trunk circuit, and means for extending' a. second telephone linoJ assigned to tlie called subscriber to the selected trunk when tlie first line of the sub seriber is busy and means for signaling); the called telephone line.

ln Witness whereof, l hereunto subscribe my name this 23rd day of February, A. D. 1920.

VINFRED T. POVELL. 

